The use of dock lights on the loading platform of a warehouse for the purpose of illuminating the interior of a truck backed up to the loading platform is well known. Typically, the base of the light is mounted to a wall on the inside of the warehouse to protect the dock light from the elements when not in use, but it includes an extendible linkage for extending the light through the door of a truck so that it can illuminate the interior of the truck.
Such an extendible dock light is disclosed in U.S. Pat. No. 5,709,458 wherein a single halogen lamp is included for obtaining the desired illumination. One disadvantage to the use of halogen lamps is that they are relatively sensitive to damage from impact and can be made inoperable if the surrounding lamp assembly is hit by a door, for example. Further, because of the relative large size of the halogen lamp, the profile of the lamp assembly is relatively large and therefore more likely to be hit by an object.
Another disadvantage to the use of halogen lamps is that, although they use less energy than an incandescent light, they still use a considerable amount of energy to light them. Further, their life is relatively short (i.e. in the range of 2,000 to 5,000 hours).